It’s a phenomenon that many parents are familiar with: their child’s obsession with a particular thing. The little one refuses point blank to leave home without their favourite toy, be it doll, dinosaur or truck. They may want to read nothing but books about princesses or aeroplanes. They’ll bombard their parents with questions from dawn until dusk.

Parents quite naturally worry that this obsession is a little unhealthy. What they might be surprised to discover is that scientific research suggests that it’s actually a positive thing.

Benefits can include an increased ability to learn, greater persistence, a heightened attention span and, unsurprisingly, a deeper knowledge of the subject itself, be it pterodactyl or steam train.

Through books, videos and toys, children are motivated to pursue their passion. In addition, they ask lots of questions. These fact-finding missions help them to understand the world around them, ultimately helping them to learn.

It’s also a confidence booster, because children with intense interests end up knowing more about their subject than their parents.

More boys than girls

Research found that boys are more likely to have an intense interest in a conceptual domain - like dinosaurs - than girls.

Or, it could be down to the fact that parents - knowingly or unknowingly - present their children with toys based on gender biases. In addition, the marketing of toys and other children’s products could lead boys and girls towards gravitate to different things.

It ends when school starts

A 2007 study found that most obsessions come to an end when school starts. This is partly because children don’t have time to follow up their interests, and partly that they are exposed to lots of new things at school.

There’s also the added social pressure: they start mixing with children who don’t share their obsession.

Ultimately, the obsession is nothing to worry about:

"In some cases, [an intense interest] is just enjoyable. It's [just] something they like," Judy DeLoache, a professor of psychology at the University of Virginia, and author of one of the studies told Live Science. "It's perfectly normal. There isn't anything weird about it."